1. Field of the Invention
This invention relates to a light emitting device with a heat dissipation member formed of aluminum, aluminum alloy, magnesium or magnesium alloy. Also, this invention relates to a method of making the light emitting device.
2. Description of the Related Art
JP-A-2006-005290 discloses a light emitting device that is composed of a high heat conductivity heat dissipation base with a die bonding mount surface, a circuit board disposed on the heat dissipation base and having a hole for exposing a part of the mount surface and a flared portion flaring outside a peripheral edge of the heat dissipation base, a light emitting element mounted through the hole and on the mount surface, and a transparent resin material for sealing the upper part of the light emitting element. The light emitting device of JP-A-2006-005290 is disposed as the heat dissipation base is contacted with the outer surface of a housing of an electric instrument.
However, the light emitting device of JP-A-2006-005290 may cause the problem that, when the housing is formed of aluminum, aluminum alloy, magnesium or magnesium alloy, oxide film will be produced on the surface of the housing such that it cannot be directly bonded to the housing via a general solder material. Therefore, a bonding sheet of an adhesive resin needs to be put between the heat dissipation base and the housing, or the heat dissipation base and the housing need to be fixed by a fastening member such as a screw. Thereby, the number of parts or production steps will increase. Furthermore, the oxide film formed on the surface of the housing will increase a thermal resistance between the heat dissipation base and the housing to lower the heat dissipation efficiency.